I'll get you pictures of the IO-520A on our 206 this evening for you.

Tim

Awesome. Thanks!


Sent from my iPhone using Tapatalk

Just a guess but I bet the diaphragm isn't leaking. Like pinecone said, when the engine is running the intake manifold drain is under vacuum and since your fuel distributor vent is connected to it, it is under vacuum also. When you go to shut down the engine the vacuum keeps the diaphragm from completely closing so your engine keeps sputtering. With the throttle open slightly there isn't as much vacuum on the drain so the engine shuts down properly from 1200rpm.

Thanks whee! I think that's the best explanation I've heard of what's happening. I don't think it's leaking either. I just got s pic from Rezdog and his IO-520-A and it just had a fitting coming off of the vent on the distributor. Pretty much what I have with the hose off minus the fitting. And short of some sort of diaphragm failure, doesn't the vent only go to the air side of the diaphragm? I'd think the potential for fuel coming out would be pretty small.

I'm looking forward to getting some flights in to verify it's stopped.


Sent from my iPhone using Tapatalk

Whee, I believe you could be correct. Actually, I have more faith in your hypothesis than my own. I trust Grassstrippilot will verify it one way or the other.

My 210 had the hose barb screwed into the fuel distributor, but no hose. The Ram STC engine upgrade called for the vent to be plumbed out through the rear baffle and out the belly along side other the other drains.

My 185 started out with just a hose barb but I wasn't comfortable with the possibility of a diaphragm failure that could spray fuel on top of the engine and leak onto an exhaust manifold. I ran a hose out the cooling duct for the fuel pump when we put the IO-550 in.

Grassstrippilot wrote:Update: I finally had some time to see where that hose went to. Ends up it Ts into the manifold drain line that exits out by the cowl flap. I pulled the hose off the manifold and zip tied it so it wouldn't flop around and so the manifold vent went to free air and, guess what!?!? Three normal shutdowns, 2 on a cold engine, one from a hot engine. All from idle throttle and a leaned out mixture.

Yep, there's your issue! Good find

Pinecone wrote:Whee, I believe you could be correct. Actually, I have more faith in your hypothesis than my own. I trust Grassstrippilot will verify it one way or the other.

My 210 had the hose barb screwed into the fuel distributor, but no hose. The Ram STC engine upgrade called for the vent to be plumbed out through the rear baffle and out the belly along side other the other drains.

My 185 started out with just a hose barb but I wasn't comfortable with the possibility of a diaphragm failure that could spray fuel on top of the engine and leak onto an exhaust manifold. I ran a hose out the cooling duct for the fuel pump when we put the IO-550 in.

Yeah I'll definitely run it by my mechanic and see how he wants to deal with it.

Last night I flew an hour over to a friends strip to spend the night and it shut down perfectly. I'm really happy about that!


Sent from my iPhone using Tapatalk

Cory,

Pics in my pictures folder. Can't seem to paste the link for some reason.

Tim

That's ok. I flew it another 3 hours with zero problems. So I'm calling victory on this one!


Sent from my iPhone using Tapatalk